Coelopidae

Robust flies, wing 3-16 mm long (McAlpine, 1998), black or grayish black, shining to subshining, depressed, with a slightly to strongly flattened thoracic dorsum. Wing unmarked, fully developed in Nearctic species, slightly to markedly reduced in two subantarctic species. (Vockeroth 1987, McAlpine 1998)